/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @author Vladimir N. Molotkov, Alexander Y. Kleymenov
 */

package org.apache.harmony.security.x509;

import org.apache.harmony.security.asn1.ASN1Implicit;
import org.apache.harmony.security.asn1.ASN1Integer;
import org.apache.harmony.security.asn1.ASN1Sequence;
import org.apache.harmony.security.asn1.ASN1Type;
import org.apache.harmony.security.asn1.BerInputStream;

/**
 * The class encapsulates the ASN.1 DER encoding/decoding work with the
 * GeneralSubtree structure which is a part of X.509 certificate: (as specified
 * in RFC 3280 - Internet X.509 Public Key Infrastructure. Certificate and
 * Certificate Revocation List (CRL) Profile.
 * http://www.ietf.org/rfc/rfc3280.txt):
 * 
 * <pre>
 * 
 *   GeneralSubtree ::= SEQUENCE {
 *        base                    GeneralName,
 *        minimum         [0]     BaseDistance DEFAULT 0,
 *        maximum         [1]     BaseDistance OPTIONAL }
 * 
 *   BaseDistance ::= INTEGER (0..MAX)
 * 
 * </pre>
 * 
 * @see org.apache.harmony.security.x509.NameConstraints
 * @see org.apache.harmony.security.x509.GeneralName
 */
public class GeneralSubtree {

	// the value of base field of the structure
	private final GeneralName base;
	// the value of minimum field of the structure
	private final int minimum;
	// the value of maximum field of the structure
	private final int maximum;
	// the ASN.1 encoded form of GeneralSubtree
	private byte[] encoding;

	/**
	 * ASN.1 DER X.509 GeneralSubtree encoder/decoder class.
	 */
	public static final ASN1Sequence ASN1 = new ASN1Sequence(new ASN1Type[] {
			GeneralName.ASN1, new ASN1Implicit(0, ASN1Integer.getInstance()),
			new ASN1Implicit(1, ASN1Integer.getInstance()) }) {
		{
			setDefault(new byte[] { 0 }, 1); // minimum 0
			setOptional(2); // maximum optional
		}

		@Override
		protected Object getDecodedObject(BerInputStream in) {
			final Object[] values = (Object[]) in.content;
			int maximum = -1; // is optional maximum missing?
			if (values[2] != null) {
				maximum = ASN1Integer.toIntValue(values[2]); // no!
			}
			return new GeneralSubtree((GeneralName) values[0],
					ASN1Integer.toIntValue(values[1]), maximum);
		}

		@Override
		protected void getValues(Object object, Object[] values) {

			final GeneralSubtree gs = (GeneralSubtree) object;

			values[0] = gs.base;
			values[1] = ASN1Integer.fromIntValue(gs.minimum);
			if (gs.maximum > -1) {
				values[2] = ASN1Integer.fromIntValue(gs.maximum);
			}
		}
	};

	/**
	 * TODO
	 * 
	 * @param base
	 *            : GeneralName
	 */
	public GeneralSubtree(GeneralName base) {
		this(base, 0, -1);
	}

	/**
	 * TODO
	 * 
	 * @param base
	 *            : GeneralName
	 * @param minimum
	 *            : int
	 */
	public GeneralSubtree(GeneralName base, int minimum) {
		this(base, minimum, -1);
	}

	/**
	 * TODO
	 * 
	 * @param base
	 *            : GeneralName
	 * @param minimum
	 *            : int
	 * @param maximum
	 *            : int
	 */
	public GeneralSubtree(GeneralName base, int minimum, int maximum) {
		this.base = base;
		this.minimum = minimum;
		this.maximum = maximum;
	}

	/**
	 * Places the string representation of extension value into the StringBuffer
	 * object.
	 */
	public void dumpValue(StringBuffer buffer, String prefix) {
		buffer.append(prefix).append("General Subtree: [\n"); //$NON-NLS-1$
		buffer.append(prefix).append("  base: ").append(base).append('\n'); //$NON-NLS-1$
		buffer.append(prefix).append("  minimum: ") //$NON-NLS-1$
				.append(minimum).append('\n');
		if (maximum >= 0) {
			buffer.append(prefix).append("  maximum: ") //$NON-NLS-1$
					.append(maximum).append('\n');
		}
		buffer.append(prefix).append("]\n"); //$NON-NLS-1$
	}

	/**
	 * Returns the value of base field of the structure.
	 * 
	 * @return base
	 */
	public GeneralName getBase() {
		return base;
	}

	/**
	 * Returns ASN.1 encoded form of this X.509 GeneralSubtree value.
	 * 
	 * @return a byte array containing ASN.1 encode form.
	 */
	public byte[] getEncoded() {
		if (encoding == null) {
			encoding = ASN1.encode(this);
		}
		return encoding;
	}

	/**
	 * Returns the value of maximum field of the structure.
	 * 
	 * @return maximum
	 */
	public int getMaximum() {
		return maximum;
	}

	/**
	 * Returns the value of minimum field of the structure.
	 * 
	 * @return minimum
	 */
	public int getMinimum() {
		return minimum;
	}
}
